The present invention relates to a liquid jetting head of a liquid jetting device, for example, a liquid jetting head such as an ink jet recording head employed in an image recording equipment such as a printer, etc., a coloring material jetting head employed to manufacture a color filter such as a liquid crystal display, etc., an electrode material jetting head employed to form electrodes of an organic EL (Electro Luminescence) display, FED (face emission display), etc., a bioorganic substance jetting head employed to manufacture a biochip (biochemical element), or the like, and a method of manufacturing the same.
The liquid jetting head has a series of channels, which are extended from a common liquid chamber to nozzle orifices via pressure generating chambers, in plural as many as the nozzle orifices. Then, in reply to the request for the higher density, respective pressure generating chambers must be formed at a fine pitch that corresponds to the density (the number of impacts of liquid droplets per unit area). Therefore, a thickness of bulkhead portions that partition adjacent pressure generating chambers becomes very thin. Also, in order to use effectively a liquid pressure in the pressure generating chambers to eject the droplet, a channel width of liquid supply ports that communicate the pressure generating chambers with a common liquid chamber is narrowed much more than a chamber width of the pressure generating chambers.
From a viewpoint of manufacturing the pressure generating chambers and the liquid supply ports, both have a fine shape, with good precision, a silicon substrate is preferably employed in the liquid jetting head, e.g., the ink jet recording head in the related art. In other words, crystal faces of the silicon substrate are exposed by the anisotropic etching, and then the pressure generating chambers and the liquid supply ports are partitioned and formed by the crystal faces.
Also, a nozzle plate in which the nozzle orifices are formed is comprised of a metal plate to satisfy the request for the workability, etc. Then, a diaphragm portion that changes volumes of the pressure generating chambers is formed in an elastic plate. This elastic plate has a double-layered structure in which a resin film is laminated on a metal supporting plate, and is fabricated by removing the supporting plate at portions that correspond to the pressure generating chambers.
Meanwhile, in the above liquid jetting head in the related art, the silicon substrate as the material is supplied as the wafer in a regular shape. Thus, the number of silicon members of the liquid jetting head, which can be fabricated from a sheet of this wafer, is limited. In other words, for example, the number of the silicon members that can be processed simultaneously by one step such as the anisotropic etching, or the like is limited. Therefore, there are problems such that above steps are disadvantageous in cost and working efficiency when the heads are to be mass-produced, and also response to the increase in size of the liquid jetting head is difficult. Also, because the solvent is employed in the etching of the silicon members, the waste liquid processing of the solvent must be sufficiently considered from a viewpoint of the environmental protection. Thus, there is such a problem that a higher cost is needed correspondingly.
Also, considerable difference in the coefficient of linear expansion exists between the silicon and the metal. Hence, when respective members of the silicon substrate, the nozzle plate, and the elastic plate are to be pasted together, such members must be adhered at a relatively low temperature while spending long time. Therefore, it is difficult to achieve improvement of the productivity, which serves as one factor to increase a production cost.
In addition, a thickness of the bulkhead portions that partition adjacent pressure generating chambers is very small and thus their rigidity is small. Therefore, there is a so-called adjacent crosstalk problem such that the ejection characteristic of the droplet is varied by the influence of the liquid pressure that is generated in the adjacent pressure generating chamber.
Also, the trial to form the pressure generating chambers in the metal substrate by the plastic working is being carried out. In this case, since the pressure generating chambers are very fine and a channel width of the liquid supply ports must be formed narrower than a chamber width of the pressure generating chambers, etc., such working is difficult. In addition, since a high precision is required of the male mold that is employed to form the pressure generating chambers and the liquid supply ports, manufacture of the male mold is difficult. Therefore, there is such a problem that it is difficult to improve the production efficiency.